The callous shooting of 11-year old Rhys Jones in a Liverpool car park in 2007 left me horrified and cold.

He was a much-loved, vivacious child, innocently walking home after football practice, when teenage wannabe gangster Sean Mercer fired a gun at a rival youth – and missed. He hit Rhys instead.

My instinctive reaction was disbelief. How and why do these things happen? What do they say about the world we live in? And how could his poor family recover from this senseless and totally unnecessary death? I knew I could never fully understand it, but I felt compelled to try.

Following the trial of Rhys’s killer and those who assisted him, I made contact with Dave Kelly, the detective who led the police investigation.

Over several years, we developed mutual respect and trust, and spent hours discussing the details and unique challenges that he encountered while trying to bring about justice.

Kelly had maintained a close bond with Rhys’s parents Mel and Steve, which helped pave the way for me to meet them. They spoke openly about life before their son’s fatal shooting, and their commitment to ensuring his death would not be in vain.

We then explored the merits of telling their story in the form of a factual drama that would move beyond what had been reported in the news and present the personal experiences behind the headlines.

I made it very clear that I could never consider such a project without their full blessing and involvement.

Without much hesitation, Steve stared me in the eye and said: “We want you to do it, and we’ll help you get it right.”

Soon afterwards, Jeff Pope came on board and together we meticulously embarked on a forensic examination of the facts.

Using his journalistic instincts and emotional intelligence, Jeff harnessed raw and honest accounts, shaping his scripts around the ripple effect of Rhys’s murder.

These scripts were both powerful and nuanced. There was a truth to them that filtered through the rest of the production. Director Paul Whittington brought a confident approach to creating a cinematic piece that was grounded in authenticity.

Working with our heads of department, he sifted through a mountain of reference material and made calculated decisions on how best to recreate the world we sought to reflect.

Stephen Graham was the natural choice to play Kelly. Having been raised in a similar environment, he understood where the detective was coming from and shared a similar temperament.

The other lead actors – Sinead Keenan, Brìan F O’Byrne, Stephen Walters and Sara Powell – added a layer of power and balance to augment Graham in the lead role.

Among the biggest (and perhaps most satisfying) surprises came from our less-well-known actors – many of whom had never been in a school play, much less a primetime drama. They filled the roles of Mercer, his gang and others who were caught in the aftermath of his actions.

Aware that these roles would be central to ensuring the credibility of the drama, our casting team, Amy Hubbard and Florence Izen-Taylor, spent months scouring the streets of Liverpool for undiscovered talent.

They became familiar faces in local boxing gyms, youth clubs and chicken shops as they engaged with streetwise youths.

Some required more persuasion than others before auditioning, but the hard work paid off when a handful of hidden gems emerged from the process.

In a story as sensitive as this one, it is inevitable that some will question our motives, or perhaps (lazily, I feel) accuse us of exploitation. The truth is that we wanted to use this story as a cautionary tale about the widespread consequences of bad choices.

The most humbling aspect of making the film was asking for, and then receiving, support from the people of Liverpool. Once they became aware of Mel and Steve’s involvement in the project, we were welcomed with open arms.

The best example of this was when 38,000 Everton supporters (along with visiting West Ham fans) at Goodison Park agreed to take part in our filming of a minute’s applause for Rhys.

It was the most moving experience of my career so far, and one I will cherish for the rest of my life.